锡酸钾对流动锌酸钾碱液中锌沉积/溶解的影响

Effect of Potassium Stannate on the Deposition/Dissolution Behavior of Zinc Anode for Zinc-nickel Single-flow Battery

研究了在流动的高浓度锌酸钾溶液中锡酸钾添加剂对锌负极沉积/溶解行为的影响.循环伏安测试结果表明,扫描速度为1 m V/s时,随着添加锡酸钾浓度的增加,阴极分支更早出现沉积,溶解峰的峰值逐渐减小;随着扫描速度的增加,这种规律变得不明显.利用SEM观测电沉积500 s的沉积物形貌发现,向基础溶液中添加锡酸钾有利于晶种的产生和晶粒的生长. EDS测试结果表明含锡酸钾的锌酸钾溶液中沉积层含有锌和锡.自放电测试结果表明,基础电解液加入锡酸钾后自放电现象得到了明显的改善,充满电静置12 h后加入0. 1 mol/L锡酸钾的电池放电库仑效率从基础溶液的60. 0%提高到81. 1%.

The effect of potassium stannate additive on the deposition/dissolution behavior of zinc anode in flowing high concentration potassium zincate solution was studied. Cyclic voltammetry results show that when the scanning speed is 1 mV/s, the cathode branch deposits earlier with the increase of potassium stannate concentration, that is, the co-deposition of tin and zinc leads to the gradual decrease of dissolution peak with the increase of potassium stannate concentration. With the increase of scanning speed, the law becomes less obvious. SEM analysis shows that the addition of potassium stannate to the base solution is beneficial to seed production and grain growth. EDS tests show that the deposit from potassium stannate solution containing potassium stannate do contain zinc and tin. The self-discharge test shows that the self-discharge phenomenon is improved obviously after adding potassium stannate to the basic electrolyte. The Coulomb efficiency of the battery with 0.1mol/L potassium stannate is increased from 60.0% of the basic solution to 81.1% after 12h static charge. Therefore, the addition of potassium stannate in high concentration potassium zincate solution can benefit the production of seed and the growth of grain, produce compact small grains, make the deposit surface smoother and more compact, slow down the self-dissolution of zinc to a certain extent, and thus inhibiting the self-discharge effect.